Biomarkers associated with the development of comorbidities in patients with atopic dermatitis: A systematic review

Trajectories of egg sensitization in childhood: Two birth cohorts in Asia and Europe

BACKGROUND

Hen's egg exposure through impaired skin barrier is considered a major mechanism of sensitization to eggs. However, the impact of filaggrin (FLG) gene loss-of-function mutations on the natural history of egg sensitization lacks consensus among studies.

OBJECTIVE

To evaluate the association between the natural course of egg sensitization and FLG mutations.

METHODS

We used Japanese and the UK birth cohorts (CHIBA and MAAS) to identify the longitudinal patterns of egg sensitization until mid-school age and examined the relationship between the identified patterns and FLG mutations. Sensitization was assessed using egg white-specific IgE levels or skin prick tests (SPTs). Egg allergy was confirmed by parental reports and sensitization. Latent class growth analysis identified longitudinal patterns.

RESULTS

Three similar patterns of egg sensitization (persistent, early-onset remitting, and no/low grade classes) were identified in both cohorts, with differing prevalence estimates. The proportion of children with egg allergy in the persistent class at 7 or 8 years of age was 23% (CHIBA) and 20% (MAAS). Consistently in both cohorts, FLG mutations were significantly associated only with the persistent class. Children with FLG mutations had an approximately four-fold increased risk of being in the persistent sensitization class (RRRs: 4.3, 95%C.I. (1.2-16.0), p = .03 in CHIBA; 4.3 (1.3-14.7), p = .02 in MAAS).

CONCLUSION

FLG loss-of-function mutations are associated with persistent egg sensitization in both Japanese and European ethnicities, and the mutations might be a potential biomarker for identifying the risk of persistent egg sensitization/allergy in early infancy. Future studies should incorporate oral food challenges to confirm this relationship.

Exploring the Complexities of Atopic Dermatitis: Pathophysiological Mechanisms and Therapeutic Approaches

Atopic dermatitis (AD) is a prevalent inflammatory skin condition impacting both children and adults globally, with a prevalence of 15-30%. It ranks as the most prevalent skin disorder based on disability-adjusted life-years by the World Health Organization. It presents with symptoms like skin irritation, redness, dryness, itchiness, and vesicular blisters and commonly coexists with other atopic symptoms like allergic rhinitis, asthma, and food allergies. The pathophysiology involves a complex interplay of genetic predispositions, immunological dysfunctions, and environmental factors leading to tissue inflammation and disrupted skin barrier integrity. Alopecia areata is characterized by nonscarring hair loss and shares correlations with AD including a higher prevalence of atopic diseases, shared intracellular mechanisms involving the JAK-STAT pathway, and potential treatment overlap such as dupilumab. These correlations could direct new areas of research and increased insight for both diseases. Treatment of AD requires a personalized approach due to its complex, multifactorial nature integrating nonpharmacological interventions like skin hydration and trigger avoidance as well as topical and systemic approaches, if necessary, with topical corticosteroids being the first line for flares; long term corticosteroid use poses risk for adverse effects like skin atrophy. Severe cases may require systemic treatments or phototherapy. Future treatment prospects include targeting the dysbiotic microbiome and identifying biomarkers for tailored therapeutic strategies, emphasizing the importance of personalized medicine in optimizing AD management.

Defining disease severity in atopic dermatitis and psoriasis for the application to biomarker research: an interdisciplinary perspective

More severe atopic dermatitis and psoriasis are associated with a higher cumulative impact on quality of life, multimorbidity and healthcare costs. Proactive, early intervention in those most at risk of severe disease may reduce this cumulative burden and modify the disease trajectory to limit progression. The lack of reliable biomarkers for this at-risk group represents a barrier to such a paradigm shift in practice. To expedite discovery and validation, the BIOMarkers in Atopic Dermatitis and Psoriasis (BIOMAP) consortium (a large-scale European, interdisciplinary research initiative) has curated clinical and molecular data across diverse study designs and sources including cross-sectional and cohort studies (small-scale studies through to large multicentre registries), clinical trials, electronic health records and large-scale population-based biobanks. We map all dataset disease severity instruments and measures to three key domains (symptoms, inflammatory activity and disease course), and describe important codependencies and relationships across variables and domains. We prioritize definitions for more severe disease with reference to international consensus, reference standards and/or expert opinion. Key factors to consider when analysing datasets across these diverse study types include explicit early consideration of biomarker purpose and clinical context, candidate biomarkers associated with disease severity at a particular point in time and over time and how they are related, taking the stage of biomarker development into account when selecting disease severity measures for analyses, and validating biomarker associations with disease severity outcomes using both physician- and patient-reported measures and across domains. The outputs from this exercise will ensure coherence and focus across the BIOMAP consortium so that mechanistic insights and biomarkers are clinically relevant, patient-centric and more generalizable to current and future research efforts.

Tape Stripping - Searching for Minimally Invasive Biomarkers in Atopic Dermatitis

Atopic dermatitis (AD) is nowadays entering a new era of more targeted treatments. However, to make personalized medicine, which we are currently striving for, a reality, a reliable set of validated biomarkers is needed. The most practical seem to be biomarkers that can be obtained easily and minimally invasively. Tape stripping (TS) is a method that provides such an opportunity. This review summarizes the potential biomarkers of AD identified by the minimally invasive TS method. Thymic stromal lymphopoietin (TSLP), interleukin (IL)-13, CC chemokine ligand 17 (CCL17)/thymus and activation-regulated chemokine (TARC) and stratum corneum (SC) lipids can be used as predictive biomarkers for AD occurrence. CCL17/TARC also holds great promise for being reliable biomarkers for AD severity as well as treatment response. Nitric oxide synthase 2 (NOS2)/inducible nitric oxide synthase (iNOS) which high expression is specific for psoriasis may be a good biomarker for differential diagnosis between psoriasis and AD in challenging clinical situations. AD children with food allergy (FA) have a unique endotype characterized by selectively altered expression of various molecules in the skin that can indicate FA coexistence. Unfortunately, although numerous potential biomarkers have been found, none of these candidates have been validated and implemented into routine clinical practice, which still separates us from the possibility of a precise approach to AD patients.

Biosignatures of defective sebaceous gland activity in sebum-rich and sebum-poor skin areas in adult atopic dermatitis

Atopic dermatitis (AD) is a composite disease presenting disruption of the skin permeability barrier (SPB) in the stratum corneum (SC). Recent evidence supports derangement of the sebaceous gland (SG) activity in the AD pathomechanisms. The objective of this study was to delineate profiles of both sebaceous and epidermal lipids and of aminoacids from SG-rich (SGR) and SG-poor (SGP) areas in AD. Both sebum and SC were sampled from SGR areas, while SC was sampled also from SGP areas in 54 adult patients with AD, consisting of 34 and 20 subjects, respectively with and without clinical involvement of face, and in 44 age and sex-matched controls. Skin biophysics were assessed in all sampling sites. Disruption of the SBP was found to be associated with dysregulated lipidome. Abundance of sapienate and lignocerate, representing, respectively, sebum and the SC type lipids, were decreased in sebum and SC from both SGR and SGP areas. Analogously, squalene was significantly diminished in AD, regardless the site. Extent of lipid derangement in SGR areas was correlated with the AD severity. The abundance of aminoacids in the SC from SGR areas was altered more than that determined in SGP areas. Several gender-related differences were found in both controls and AD subgroups. In conclusion, the SG activity was differently compromised in adult females and males with AD, in both SGR and SGP areas. In AD, alterations in the aminoacidome profiles were apparent in the SGR areas. Lipid signatures in association with aminoacidome and skin physical properties may serve the definition of phenotype clusters that associate with AD severity and gender.

Maternal prepregnancy body mass index, gestational weight gain, and allergic diseases in children: A systematic review and meta-analysis

Several studies have investigated a link between maternal preconception body mass index, gestational weight gain (GWG), and the risk of childhood allergic diseases, but the conclusions of these studies were inconsistent. This review aimed to evaluate the relationship based on existing studies. We eventually included 18 cohort studies. The findings indicated that both maternal preconception overweight or obesity increased the risk of childhood wheezing (overweight: risk ratio (RR) 1.09, 95% confidence interval (CI) 1.04-1.15; obesity: RR 1.24, 95% CI 1.12-1.38) and asthma (overweight: RR 1.18, 95% CI 1.05-1.32; obesity: RR 1.34, 95% CI 1.13-1.58), and the risk of childhood wheezing increased with continuous prepregnancy BMI changes (per 5 kg/m2 increase) (RR 1.10, 95% CI 1.05-1.15). Preconception underweight may elevate the risk of childhood eczema ever (RR 1.05, 95% CI 1.02-1.09) and current eczema (RR 1.20, 95% CI 1.05-1.37), and preconception overweight may reduce the risk of childhood eczema ever (RR 0.98, 95% CI 0.96-0.99). No statistically significant association between GWG and the risk of allergic diseases in children was found. Preconception weight management is encouraged for the prevention of allergic diseases in children.

Atopic March or Atopic Multimorbidity-Overview of Current Research

The atopic march encompasses a sequence of allergic conditions, including atopic dermatitis, food allergy, allergic rhinitis, and asthma, that frequently develop in a sequential pattern within the same individual. It was introduced as a conceptual framework aimed at elucidating the developmental trajectory of allergic conditions during childhood. Following the introduction of this concept, it was initially believed that the atopic march represented the sole and definitive trajectory of the development of allergic diseases. However, this perspective evolved with the emergence of new longitudinal studies, which revealed that the evolution of allergic diseases is far more intricate. It involves numerous immunological pathological mechanisms and may not align entirely with the traditional concept of the atopic march. The objective of our review is to portray the atopic march alongside other patterns in the development of childhood allergic diseases, with a specific emphasis on the potential for a personalized approach to the prevention, diagnosis, and treatment of atopic conditions.

The origins and longevity of IgE responses as indicated by serological and cellular studies in mice and humans

The existence of long-lived IgE antibody-secreting cells (ASC) is contentious, with the maintenance of sensitization by the continuous differentiation of short-lived IgE+ ASC a possibility. Here, we review the epidemiological profile of IgE production, and give an overview of recent discoveries made on the mechanisms regulating IgE production from mouse models. Together, these data suggest that for most individuals, in most IgE-associated diseases, IgE+ ASC are largely short-lived cells. A subpopulation of IgE+ ASC in humans is likely to survive for tens of months, although due to autonomous IgE B cell receptor (BCR) signaling and antigen-driven IgE+ ASC apoptosis, in general IgE+ ASC probably do not persist for the decades that other ASC are inferred to do. We also report on recently identified memory B cell transcriptional subtypes that are the likely source of IgE in ongoing responses, highlighting the probable importance of IL-4Rα in their regulation. We suggest the field should look at dupilumab and other drugs that prohibit IgE+ ASC production as being effective treatments for IgE-mediated aspects of disease in most individuals.

A concept for integrated care pathways for atopic dermatitis-A GA2 LEN ADCARE initiative

INTRODUCTION

The integrated care pathways for atopic dermatitis (AD-ICPs) aim to bridge the gap between existing AD treatment evidence-based guidelines and expert opinion based on daily practice by offering a structured multidisciplinary plan for patient management of AD. ICPs have the potential to enhance guideline recommendations by combining interventions and aspects from different guidelines, integrating quality assurance, and describing co-ordination of care. Most importantly, patients can enter the ICPs at any level depending on AD severity, resources available in their country, and economic factors such as differences in insurance reimbursement systems.

METHODS

The GA2 LEN ADCARE network and partners as well as all stakeholders, abbreviated as the AD-ICPs working group, were involved in the discussion and preparation of the AD ICPs during a series of subgroup workshops and meetings in years 2020 and 2021, after which the document was circulated within all GAL2 EN ADCARE centres.

RESULTS

The AD-ICPs outline the diagnostic procedures, possible co-morbidities, different available treatment options including differential approaches for the pediatric population, and the role of the pharmacists and other stakeholders, as well as remaining unmet needs in the management of AD.

CONCLUSION

The AD-ICPs provide a multidisciplinary plan for improved diagnosis, treatment, and patient feedback in AD management, as well as addressing critical unmet needs, including improved access to care, training specialists, implementation of educational programs, assessment on the impact of climate change, and fostering a personalised treatment approach. By focusing on these key areas, the initiative aims to pave the way for a brighter future in the management of AD.

Disease modification in inflammatory skin disorders: opportunities and challenges

Progress in understanding of the mechanisms underlying chronic inflammatory skin disorders, such as atopic dermatitis and psoriasis vulgaris, has led to new treatment options with the primary goal of alleviating symptoms. In addition, this knowledge has the potential to inform on new strategies aimed at inducing deep and therapy-free remission, that is, disease modification, potentially impacting on associated comorbidities. However, to reach this goal, key areas require further exploration, including the definitions of disease modification and disease activity index, further understanding of disease mechanisms and systemic spillover effects, potential windows of opportunity, biomarkers for patient stratification and successful intervention, as well as appropriate study design. This Perspective article assesses the opportunities and challenges in the discovery and development of disease-modifying therapies for chronic inflammatory skin disorders.

[Molecular diagnosis of hand eczema]

BACKGROUND

Because hand eczema is a diagnostic challenge even for experienced dermatologists, a correct diagnosis is essential to ensure success of specific therapies.

OBJECTIVES

Prerequisites for successful molecular diagnostics in general and in hand eczema in particular are discussed.

MATERIALS AND METHODS

Basic research and opinion statement on new developments in molecular diagnostics are considered with a special focus on hand eczema.

RESULTS

The first molecular classifier to distinguish psoriasis from (hand) eczema signature has been introduced as CE-marked in vitro diagnostics (CE-IVD); many more biomarkers associated with diagnostics, theranostics, or natural course of the disease are currently being investigated.

CONCLUSIONS

Diagnosis of hand eczema will be supported by molecular diagnostics in the near future; we are at the beginning of the molecular era in dermatology.